|The way to test a nic card is to have a software app and/or a loopback connector. Both are better. You might have something like an intel or other large name brand that has installed already a modest test or tech support app already on your system. I'd use that first. Then get my trusty looback or do a ping to a known working nic in the same subnet.|
The 127 deal is about useless for the most part.
What your question is, is that you can't connect. What I read is that your system connects to a dsl/cable modem. I would suggest that you contact the ISP to see how they troubleshoot it. The reason is you kind of have two issues. One is the isp (logon)and the other is the hardware. If they suggest it is a hardware issue from modem to your computer then repost your findings.